The Nagin is a protector and defender. she is shown to swallow people who are horrible abusive and criminal to kids.  She turned into a half snake, half human creature. When it was innocent people she sees she can swallow them but the acids do not kill them knowing that her belly only kills criminals and not children and people. She is a shape-shifting cobra that can change into a human. Her scales skin are only on the large squishybelly and her breasts. But her human hands and arms remain human